I have NEVER won at a stake higher than my normal game at the time.
When I moved up to 3/6 from 2/4 i lost like 6k, then moved back down. 5/10 I lost ~15k. 10/20 I lost probably 30k before winning. At 25/50 i was stuck 80k i think before winning. 50-100 I am now stuck 100k, so looks like things are right on track.